The present invention is directed to hot melt or phase change inks. More specifically, the present invention is directed to phase change inks particularly suitable for use in phase change ink jet printers. One embodiment of the present invention is directed to a phase change ink composition comprising (a) a colorant and (b) a carrier comprising a polyamide, wherein the polyamide component of the carrier contains at least about 10 percent by weight of a branched triamide. Another embodiment of the present invention is directed to a phase change ink composition comprising (a) a colorant and (b) a phase change ink carrier comprising a polyamide, wherein the polyamide component of the carrier contains at least about 10 percent by weight of a branched triamide which is the reaction product of either (i) a mixture consisting essentially of at least one monoacid, at least one branched triamine, and optional ingredients nonreactive with the monoacid, the triamine, and the reaction product thereof, or (ii) a mixture consisting essentially of at least one monoamine, at least one branched triacid, and optional ingredients nonreactive with the triacid, the monoamine, and the reaction product thereof. Yet another embodiment of the present invention is directed to a phase change ink composition comprising (a) a colorant and (b) a phase change ink carrier comprising a polyamide, wherein the polyamide component of the carrier contains at least about 10 percent by weight of a branched triamide which is the reaction product of either (i) a mixture comprising at least one branched triamine and at least one monoacid present in an amount of at least about 3 moles of monoacid per every one mole of branched triamine, or (b) a mixture comprising at least one branched triacid and at least one monoamine present in an amount of at least about 2.5 moles of monoamine per every one mole of branched triacid.
In general, phase change inks (sometimes referred to as “hot melt inks”) are in the solid phase at ambient temperature, but exist in the liquid phase at the elevated operating temperature of an ink jet printing device. At the jet operating temperature, droplets of liquid ink are ejected from the printing device and, when the ink droplets contact the surface of the recording substrate, either directly or via an intermediate heated transfer belt or drum, they quickly solidify to form a predetermined pattern of solidified ink drops. Phase change inks have also been used in other printing technologies, such as gravure printing, as disclosed in, for example, U.S. Pat. No. 5,496,879 and German Patent Publications DE 4205636AL and DE 4205713AL, the disclosures of each of which are totally incorporated herein by reference.
Phase change inks for color printing typically comprise a phase change ink carrier composition which is combined with a phase change ink compatible colorant. In a specific embodiment, a series of colored phase change inks can be formed by combining ink carrier compositions with compatible subtractive primary colorants. The subtractive primary colored phase change inks can comprise four component dyes, namely, cyan, magenta, yellow and black, although the inks are not limited to these four colors. These subtractive primary colored inks can be formed by using a single dye or a mixture of dyes. For example, magenta can be obtained by using a mixture of Solvent Red Dyes or a composite block can be obtained by mixing several dyes. U.S. Pat. No. 4,889,560, U.S. Pat. No. 4,889,761, and U.S. Pat. No. 5,372,852, the disclosures of each of which are totally incorporated herein by reference, teach that the subtractive primary colorants employed can comprise dyes from the classes of Color Index (C.I.) Solvent Dyes, Disperse Dyes, modified Acid and Direct Dyes, and Basic Dyes. The colorants can also include pigments, as disclosed in, for example, U.S. Pat. No. 5,221,335, the disclosure of which is totally incorporated herein by reference. U.S. Pat. No. 5,621,022, the disclosure of which is totally incorporated herein by reference, discloses the use of a specific class of polymeric dyes in phase change ink compositions.
Phase change inks have also been used for applications such as postal marking, industrial marking, and labelling.
Phase change inks are desirable for ink jet printers because they remain in a solid phase at room temperature during shipping, long term storage, and the like. In addition, the problems associated with nozzle clogging as a result of ink evaporation with liquid ink jet inks are largely eliminated, thereby improving the reliability of the ink jet printing. Further, in phase change ink jet printers wherein the ink droplets are applied directly onto the final recording substrate (for example, paper, transparency material, and the like), the droplets solidify immediately upon contact with the substrate, so that migration of ink along the printing medium is prevented and dot quality is improved.
Compositions suitable for use as phase change ink carrier compositions are known. Some representative examples of references disclosing such materials include U.S. Pat. No. 3,653,932, U.S. Pat. No. 4,390,369, U.S. Pat. No. 4,484,948, U.S. Pat. No. 4,684,956, U.S. Pat. No. 4,851,045, U.S. Pat. No. 4,889,560, U.S. Pat. No. 5,006,170, U.S. Pat. No. 5,151,120, U.S. Pat. No. 5,372,852, U.S. Pat. No. 5,496,879, European Patent Publication 0187352, European Patent Publication 0206286, German Patent Publication DE 4205636AL, German Patent Publication DE 4205713AL, and PCT Patent Application WO 94/04619, the disclosures of each of which are totally incorporated herein by reference. Suitable carrier materials can include paraffins, microcrystalline waxes, polyethylene waxes, ester waxes, fatty acids and other waxy materials, fatty amide containing materials, sulfonamide materials, resinous materials made from different natural sources (tall oil rosins and rosin esters, for example), and many synthetic resins, oligomers, polymers, and copolymers.
U.S. Pat. No. 4,830,671 (Frihart et al.), the disclosure of which is totally incorporated herein by reference, discloses an ink composition having the properties of stability and uniformity of performance under ink jet printing conditions and desired printing properties which can be obtained with hot melt ink compositions consisting of a resinous binder comprised of a compound of the formula wherein R1 represents a polymerized fatty acid residue with two carboxylic acid groups removed, R2 and R3 are the same or different and each represent an alkylene with up to 12 carbon atoms, a cycloalkylene with 6 to 12 carbon atoms, an arylene with 6 to 12 carbon atoms, or an alkarylene with 7 to 12 carbon atoms, and R4 and R5 are the same or different and each represents an alkyl having up to 36 carbon atoms, a cycloalkyl having up to 36 carbon atoms and aryl having up to 36 carbon atoms, or an alkaryl having up to 36 carbon atoms, said resinous binder having a melt viscosity of less than 250 CPS at 50° C. and a colorant distributed through the resinous binder in an effective amount sufficient to impart a predetermined color to the resulting hot melt ink composition.
U.S. Pat. No. 5,194,638 (Frihart et al.), the disclosure of which is totally incorporated herein by reference, discloses a resinous binder for use in hot melt ink compositions, which ink compositions may be used in hot melt ink jet printing applications. The resinous binder has a melt viscosity of 250 cps or less at 150° C., is sufficiently transparent to allow a colorant to be distributed through the resinous binder in an amount effective to import a pre-determined color to the resulting hot melt ink composition, and has a blocking temperature greater than 100° C.
U.S. Pat. No. 5,645,632 (Pavlin), the disclosure of which is totally incorporated herein by reference, discloses solid diesters for hot-melt inks which are prepared by reaction of polymerized fatty acid with long chain primary monohydric alcohols, optionally in the presence of diamine. The long chain alcohols have at least about 20 carbon atoms, and preferably have 24 or more carbon atoms. The esterification of liquid polymerized fatty acid with monohydric alcohol provides a diester that is solid at room temperature and has a melting point of less than about 150° C. The diester can be formulated with colorants and/or other image-producing materials to provide an ink for hot-melt printing, e.g., hot-melt ink jet, gravure or intaglio printing.
U.S. Pat. No. 5,863,319 (Baker et al.), the disclosure of which is totally incorporated herein by reference, discloses a thermally stable ink for use in ink jet printing contains an ester amide resin, a tackifying resin, and a colorant,
U.S. Pat. No. 6,174,937 (Banning et al.), the disclosure of which is totally incorporated herein by reference, discloses a phase change ink comprising a material of the formula wherein X1, X2, X3, and X4 are segments comprising atoms selected from groups V and VI of the periodic table; wherein at least one R1 and R5 comprises at least 37 carbon units; and wherein R2, R3, and R4 each comprise at least one carbon unit. The invention further encompasses a composition of matter, as well as methods of reducing coefficients of friction of phase change ink formulations.
U.S. Pat. No. 4,889,560 (Jaeger et al.), the disclosure of which is totally incorporated herein by reference, discloses a phase change ink carrier composition combined with a compatible colorant to form a phase change ink composition. A thin film of substantially uniform thickness of that phase change ink carrier composition, and the ink produced therefrom, has a high degree of lightness and chroma. The thin films of a substantially uniform thickness of the ink composition are also rectilinearly light transmissive. The carrier composition is preferably a fatty amide-containing compound.
U.S. Pat. No. 4,889,761 (Titterington et al.), the disclosure of which is totally incorporated herein by reference, discloses a method for producing a light-transmissive phase change ink printed substrate which comprises providing a substrate, and then printing on at least one surface of the substrate a predetermined pattern of a light-transmissive phase change ink which initially transmits light in a non-rectilinear path. The pattern of solidified phase change ink is then reoriented to form an ink layer of substantially uniform thickness. This ink layer will, in turn, produce an image which then will transmit light in a substantially rectilinear path. In one aspect of the invention, the substrate is light transmissive, and the reoriented printed substrate exhibits a high degree of lightness and chroma, and transmits light in a substantially rectilinear path. In this way, the reoriented printed substrate can be used in a projection device to project an image containing clear, saturated colors.
U.S. Pat. No. 5,597,856 (Yu et al.), the disclosure of which is totally incorporated herein by reference, discloses phase change inks capable of passing light therethrough which are suitable for color overhead transparencies, as well as plain paper printing. A composition for the ink carrier comprises an unsaturated bis-amide as a transparency enhancer, a low viscosity monoamide as a thinner material, and a polyamide resin as a base and binder.
British Patent GB 2 238 792, the disclosure of which is totally incorporated herein by reference, discloses a coating composition comprising a film-forming resinous component together with a liquid carrier thereafter, in which composition the film-forming resinous component contains a film-forming polyamide containing fluorine atoms.
U.S. Pat. No. 5,372,852 (Titterington et al.), the disclosure of which is totally incorporated herein by reference, discloses a phase change ink composition that is indirectly applied to a substrate by raising the temperature of the phase change ink composition to form a liquid phase change ink composition, applying droplets of the phase change ink composition in a liquid phase to a liquid intermediate transfer surface on a solid support in a pattern using a device such as an ink jet printhead, solidifying the phase change ink composition on the liquid intermediate transfer surface, transferring the phase change ink composition from the liquid intermediate transfer surface to the substrate, and fixing the phase change ink composition to the substrate. The phase change ink composition is malleable when the ink is transferred from the intermediate transfer surface to the substrate and is ductile after the ink has been transferred to the substrate and cooled to ambient temperature to preclude the ink from crumbling and cracking.
U.S. Pat. No. 4,895,982 (Pavlin et al.), the disclosure of which is totally incorporated herein by reference, discloses tricarboxylic acids that are prepared by reacting unsaturated mono- and dicarboxylic acids of specific carbon atom content in the presence of a catalytic proportion of an unactivated clay and water. The product acids of 34, 35, 36, 38, or 40 carbon atoms are useful as corrosion inhibitors, epoxy resins curing agents, lubricants, polymeric resin plasticizers and intermediates for synthetic polymeric resins.
U.S. Pat. No. 4,066,585 (Schepp et al.), the disclosure of which is totally incorporated herein by reference, discloses intaglio and flexographic printing processes employing solvent-free inks, solid at room temperature but molten at printing temperatures, and inks suitable therefor, said inks comprising a pigment and a thermoplastic binder having a softening point between 90° C. and 160° C., said binder comprising a synthetic polyamide resin or synthetic polyesteramide resin, each resin being the condensation product of (1) an acid component comprising a dimerized fatty acid and a monocarboxylic acid and (2) an amine component comprising a diamine and, in the case of the polyesteramide resin, additionally comprising a diol and/or alkanolamine.
U.S. Pat. No. 3,622,604 (Drawert et al.), the disclosure of which is totally incorporated herein by reference, discloses synthetic polyamides, useful as binders in the formulation of printing inks, formed between a dimeric fatty acid, an unsubstituted lower aliphatic monocarboxylic acid, ethylene diamine, and certain aromatic, cycloaliphatic, and other aliphatic diamines, including aliphatic ether diamines, and methods for preparing such amides.
U.S. Pat. No. 3,253,940 (Floyd et al.), the disclosure of which is totally incorporated herein by reference, discloses polyamide resins and solutions thereof suitable for use as flexographic ink vehicles, and particularly alcohol solutions of polyamides obtained by reacting a mixture comprising polymeric fat acids, alkylene polyamines, and a low aliphatic monobasic acid.
U.S. Pat. No. 5,510,821 (Jones et al.), the disclosure of which is totally incorporated herein by reference, discloses an ink stick shape for use in a printer ink stick feed chute wherein the opposing sides of the ink stick are tapered or angled from the horizontal so that at least one area intermediate the top and the bottom of the ink stick is a greater distance from the horizontal than the junction of the side walls and the bottom of the ink stick. The ink stick shape or geometry may be keyed to a particular color.
U.S. Pat. No. 5,988,805 (Meinhardt), the disclosure of which is totally incorporated herein by reference, discloses an ink stick shape for use in a printer ink stick feed chute wherein the opposing sides of the ink stick are tapered or angled from the horizontal so that at least one area intermediate the top and the bottom of the ink stick is a greater distance from the horizontal than the junction of the side walls and the bottom of the ink stick. The ink stick shape or geometry may be keyed to a particular color.
U.S. Pat. No. 6,133,353 (Bui et al.), the disclosure of which is totally incorporated herein by reference, discloses a solubilizing agent and a compound made by reacting selected nucleophiles, including fatty acid reactants and amines with an isocyanate. The addition of the isocyanate and the different nucleophiles will create a di-urethane tetra-amide solubilizing agent product. The polyamide-solubilizing agent is useful as an ingredient in a phase change solid imaging material and as carrier compositions used to make phase change ink jet inks.
U.S. Pat. No. 6,528,613 (Bui et al.), the disclosure of which is totally incorporated herein by reference, discloses a solubilizing agent and a compound made by reacting selected nucleophiles, including fatty acid reactants and amines with an isocyanate. The addition of the isocyanate and the different nucleophiles will create a di-urethane tetra-amide solubilizing agent product. The polyamide-solubilizing agent is useful as an ingredient in a phase change solid imaging material and as carrier compositions used to make phase change ink jet inks.
U.S. Pat. No. 5,777,023 (Pavlin), the disclosure of which is totally incorporated herein by reference, discloses solid compositions containing diamidediurethanes that are useful as components of hot-melt inks. Diamidediurethanes may be prepared by reaction of a hydroxycarboxylic acid and/or lactone with either (1) monoamine and diisocyanate or (2) diamine and monoisocyanate. Alternatively, the diamidediurethane may be prepared by reacting a non-hydric carboxylic acid and/or anhydride with a hydroxyamine and a diisocyanate. The reactant identity and stoichiometry, as well as the reaction conditions, may be tailored to optimize the formation of diamidediurethane in preference to high molecular weight oligomers. The hot-melt inks may be used in ink jet, flexographic, gravure and intaglio printing.
While known compositions and processes are suitable for their intended purposes, a need remains for improved phase change inks. In addition, a need remains for phase change inks having ink carriers having improved miscibility with polyethylene waxes. Further, a need remains for phase change inks containing branched, rather than linear, amide carriers. Additionally a need remains for phase change inks containing amide carriers with reduced viscosity. There is also a need for phase change inks containing amide carriers having desirably low melting points compared to other amides of similar molecular weight and similar ratio of amide groups to hydrocarbon portion.